“We are not considering that option," he said in an interview. “We have very defined assets and capital that we want to put at work in the investment bank, and the business model works. Therefore, there is no necessity for us to make changes."

Mr Ermotti denied a report by Mediobanca analysts last week that Zurich-based UBS may dispose of the investment-banking business as higher capital requirements from regulators thwart efforts to boost returns. Mr Ermotti is reorganising the bank to cut 10,000 jobs and exit most debt-trading businesses and concentrate on money management to boost profitability.

The lender’s plan to boost return on equity to 15 per cent will be delayed by at least a year from the earlier target of 2015 after the Swiss regulator asked it to hold more capital for litigation risks, UBS said in October. Days later, Swiss Finance Minister Eveline Widmer-Schlumpf said leverage ratios are too low and banks may have to consider whether to keep securities business.

“The businesses that may be affected the most by a higher leverage ratio is our mortgage portfolio, is our corporate loan portfolio in Switzerland," Mr Ermotti said.

“To imply necessarily that a higher leverage ratio means that the investment bank is the one most affected is too much of a simple conclusion."

A standalone investment bank run by the unit’s current chief, Andrea Orcel, could earn a return on tangible equity of 14.4 per cent by 2017, according to Mediobanca. While the smaller UBS would suffer a loss of earnings from the investment bank, it would benefit from a lower risk profile. A spin-off could offer shareholders a 14 per cent upside, analyst Christopher Wheeler wrote to clients.

UBS will boost its common equity ratio to 13 per cent by the end of this year, Mr Ermotti said, reiterating an earlier target. The bank will start paying out more than 50 per cent of profit as dividends after it reaches the goal.